/**
 * jQuery upload v1.2
 * http://www.ponxu.com
 *
 * @author xwz
 */
(function($) {
        var noop = function(){ return true; };
        var frameCount = 0;
        
        $.uploadDefault = {
                url: '',
                fileName: 'filedata',
                dataType: 'json',
                params: {},
                onSend: noop,
                onSubmit: noop,
                onComplate: noop
        };

        $.upload = function(options) {
                var opts = $.extend(jQuery.uploadDefault, options);
                if (opts.url == '') {
                        return;
                }
                
                var canSend = opts.onSend();
                if (!canSend) {
                        return;
                }
                
                var frameName = 'upload_frame_' + (frameCount++);
                var iframe = $('<iframe style="position:absolute;top:-9999px" />').attr('name', frameName);
                var form = $('<form method="post" style="display:none;" enctype="multipart/form-data" />').attr('name', 'form_' + frameName);
                form.attr("target", frameName).attr('action', opts.url);
                
                // form中增加数据域
                var formHtml = '<input type="file" name="' + opts.fileName + '" onchange="onChooseFile(this)">';
                for (key in opts.params) {
                        formHtml += '<input type="hidden" name="' + key + '" value="' + opts.params[key] + '">';
                }
                form.append(formHtml);

                iframe.appendTo("body");
                form.appendTo("body");
                
                form.submit(opts.onSubmit);
                
                // iframe 在提交完成之后
                iframe.load(function() {
                        var contents = $(this).contents().get(0);
                        var data = $(contents).find('body').text();
                        if ('json' == opts.dataType) {
                                data = window.eval('(' + data + ')');
                        }
                        opts.onComplate(data);
                        setTimeout(function() {
                                iframe.remove();
                                form.remove();
                        }, 5000);
                });
                
                // 文件框
                var fileInput = $('input[type=file][name=' + opts.fileName + ']', form);
                fileInput.click();
        };
})(jQuery);

// 选中文件, 提交表单(开始上传)
var onChooseFile = function(fileInputDOM) {
        var form = $(fileInputDOM).parent();
        form.submit();
};